Socket



' N. R. SMITH 2,269,605

sodxm Filed March 31, 1939 01 m? SURFACE REG/01v WORK HARDENED BY manna/41a INVENTORY ATTORNEY.

Patented Jan. 13, 1942 UETE socxn'r Newell a. Smith, Bloomfield, N. a, assignor to Radio Corporation oi America, a corporation of Delaware Application March 31, 1939, Serial No. 265,091

Claims.

My invention relates to electrical receptacles,

particularly to sockets for receiving the contact pins of radio tubes or connectors such as terminal plugs.

One conventional socket for radio tubes comprises a molded resin body for holding a number s of circularly arranged contactors which receive the contact pins of the radio tube. The contactors are usually designed to grip the sides of thepins, one common contactor being a tube or cylinder rolled from sheet metal, into which the contact pins may be telescoped. Since the cold working of the sheet metal when bent into the cylinder places the outer metal fibers of the cylinder under tension and causes the cylinder to spring open along the seam and away from the sides of the pin, reasonably firm contact between the cylinder and pin can be obtained only by rolling it from relatively heavy sheet metal stock. When, however, the contactors must be made in sizes smaller than certain limiting values, because of close pin spacing, the thickness of the contactor sheet material is limited, the strength and resiliency is lessened and the rolled type of contactor becomes impractical.

An object of my invention is an electrical receptacle with tubular contactors that are strong, yet resilient.

Another object of my invention is an electrical receptacle with tubular contactors that may be made in very 'small sizes with the necessary strength and resiliency for good electrical connections.

The characteristic features of my invention are defined with particularity in the appended claims and one embodiment is described in the following specification and shown in the accompanying drawing in which Figure l is a perspective view of my improved socket and an associated radio tube, Figure 2 is a plan view of my socket, Figure 3 is a longitudinal sectional view of my improved socket and Figure 4 is a detailed view of one type of contactor constructed according to my invention, and Figure 5 is a cross sectional view of my improved contactor on a line 5-5 through the contact barrel.

My improved socket may be smaller in size than sockets of conventional construction and is particularly adapted for miniature radio tubes of the type shown in Figure 1 in which the contact pins I are the outer ends of lead-in conductors embedded in a glass disc or header 2 at the end of the envelope 3. The contact pins are telescoped into the female butt seamed tubular are slightly less than the pins to yieldingly yet firmly hold the pins. When the pin is inserted butted edges of the seam 4a are sprung apart. My socket comprises a round body 5 of insulating material, such as"Bake1ite with sufiicient length to accommodate my novel contactors and with an outside diameter about equal to the diameter of the radio tube. Straight sided round holes 6 in the socket body are slightly larger/than the contactors and are of uniform diameter from the top of the socket to near the bottom of the socket where the holes are constricted to provide an annular ledge 1 upon which may rest an annular beveled or rounded shoulder 8 around thetubular body of the contactor.

My improved contactor shown in detail in Fi ures 3 and 4 comprises a one-piece wrapped tube with the butt seam to along one side and with a boss or bead 9 integral with the pin receiving clip .or contact barrel l0 and the contactor shaft H. A flare or funnel l2 at the upper end of the barrel guides the pins into th barrel and strengthens the side walls of the barrel. The rounded shoulder 8 at the bottom of the bead may be substantially spherical in cross section socket joint at the shoulder and ledge prevents strains in any irregularly placed contact pins of u the tube.

In manufacturing my novel contactor, according to one characteristic feature of my invention,

a wrapped butt seam tube is swaged to reduce the diameter of the tube and to obtain the desired configuration. It has been found that rapidly delivered hammer blows upon the outer surface of the tube as it is rotated between the hammers reduce the diameter of the tube without materlally distorting the tube and as the metal is worked and the diameter is reduced. the metal in the outer layers or outer surface region of the tube is permanently hardened, apparently placing the metal fibers in the outer surface or the cylinder under compression, and forcing the butted edges of the wrapped stock into firm pressure contact; Any force from the inside of the swaged and work-hardened or strain-hardened cylinder tending to separate the butted edges of the seam must overcome the permanent strains I in the metal, and the sides of contact pins pushed metal contactors I, the inside diameters'of which into the end of the strain hardened cylinders are subjected to a pressure considerably in excess of the pressure that could be applied by a strain relieved cylinder of the same size.

The contact barrel l integral at each end with a shoulder or conical section of the contactor is, in the specific embodiment shown, particularly strong. The shoulders or sections of the con tactor not parallel to the center line of the contactor reinforce the contact barrel and increase the force necessary to separate the butted edges of the seam along the side of the barrel.

The pins may conveniently be locked in the socket by pinching the contactor shaft ill just below the lower face of the socket as shown. at H. To facilitate soldering several wires to the lower ends of the shafts number of coaxial grooves may be swaged or rolled into the lower ends of the shafts as shown. I

To electrostatically shield the several contactors and to intercept-electrostatic lines of force between the contactors a tubular shield i3 disposed centrally in the socket has been found to be effective. Electrostatic shielding between the contactors and from external electrical disturbances is particularly effective in my improved socket because the metal plate of the chassis in which the socket is set may be brought in close to the periphery of shield iii. The contactors lie in a circle between and concentric with the center shield l3 and encircling metal chassis, and because of the small size of my contactors the radial distance between the shield and chassis may be small. The socket body 5 is substantially the diameter of the tube which it receives and is securely locked in a hole in the chassis plate of the diameter of the socket. Ears are struck up from' opposite dges of the hole leaving notches in the side of the hole to receive locking lug 2i. By bringing the locking lug into registry with the notches the socket may be lowered into place bringing the lower edge of flange 22 to rest on the upper edge of the plate. The socket is then rotated to move the lug 2| into locking engagement with the holeand to bring the recesses 23 in the flange opposite the ears 20. By bending the earsinto the recesses 23 the socket is locked against rotation and is secured against removal.

The contact pins in one tube for which my socket is adapted are less than .040 inch in diameter, spaced about .1 25 inch apart in a circle only .375 inch in diameter, the largest diameter of the contactors for -the socket of this tube being less than .085 inch. The strain hardened contactor of my invention may be made in small barrel to firmly grip contact pins of the smallest size, and small overall dimension of the contactor permits close spacing between the center shield and the metal periphery of the chassis. Thecontactors of my improved electrical receptacle are strong yet resilient, are rugged in constructionand easy to manufacture.

I claim:

1. ,A female metal contactor for a socket,

adapted to internally receive a contact pin, comprising a sheet metal member wrapped to form a tube with acontact barrel having a-seam along its side, the barrel being externally swaged on its outer surface to place permanent strains in the outer surface region of its wall tending to bring the edges of the sheet along the seam together and to close said barrel upon said pin.

2. A female socket contactor comprising a sheet metal member wrapped to form a butt seamed tube with a contact barrel portion, said portion being externally swaged to a predetermined inside diameter, the metal in the outer surface region of the tube wall being work hardened by swaging to place permanent strains in the wall of the tube that will resist enlargement of the barrel diameter.

3. A female socket contactor adapted to internally receive a male contact element comprising a sheet metal member wrapped to form a tube having a butt seam along its side, the outer surface of the tube being permanently hardened by hammering to close the edges of said member along the seam.

4. A female socket contactor adapted to internally receive a male contact element comprising a sheet metal member wrapped to form a tube having a butt' seam along its side, the wall of the tube being externally swaged on its outer surface to place permanent strains in the wall tending to bring together the edges of the tube along the seam, one section of the tube being externally swaged to a diameter smaller than the tube.

'5. A female metal contactor for a socket adapted to internally receive acontact pin comprising a sheet metal member wrapped to form a tube with a contact barrel having 5 earn along its side, the barrel being externally lwaged on its outer surface to permanently work-harden the wall of the tube and place strains in the wall of the tube which tend to bring the edges of the sheet along the seam together and to close said barrel upon said pin.

NEWELL B. SMITH. 

